A new implementation of LVM copy-on-write (cow) snapshots is available in Red Hat Enterprise Linux 6.3 as a Technology Preview. The main advantage of this implementation, compared to the previous implementation of snapshots, is that it allows many virtual devices to be stored on the same data volume. This implementation also provides support for arbitrary depth of recursive snapshots (snapshots of snapshots of snapshots . . . . . . ).

This feature is for use on a single system. It is not available for multi-system access in cluster environments.

For more information, refer to the documentation of the -s/--snapshot option in the lvcreate man page.

Package: lvm2-2.02.95-10

Logical Volumes (LVs) can now be thinly provisioned to manage a storage pool of free space to be allocated to an arbitrary number of devices when needed by applications. This allows creation of devices that can be bound to a thinly provisioned pool for late allocation when an application actually writes to the pool. The thinly-provisioned pool can be expanded dynamically if and when needed for cost-effective allocation of storage space. In Red Hat Enterprise Linux 6.3, this feature is introduced as a Technology Preview. You must have the device-mapper-persistent-data package installed to try out this feature. For more information, refer to the lvcreate(8) man page.

Package: lvm2-2.02.95-10

Most LVM commands require an accurate view of the LVM metadata stored on the disk devices on the system. With the current LVM design, if this information is not available, LVM must scan all the physical disk devices in the system. This requires a significant amount of I/O operations in systems that have a large number of disks.

The purpose of the lvmetad daemon is to eliminate the need for this scanning by dynamically aggregating metadata information each time the status of a device changes. These events are signaled to lvmetad by udev rules. If lvmetad is not running, LVM performs a scan as it normally would.

This feature is provided as a Technology Preview and is disabled by default in Red Hat Enterprise Linux 6.3. To enable it, refer to the use_lvmetad parameter in the /etc/lvm/lvm.conf file, and enable the lvmetad daemon by configuring the lvm2-lvmetad init script.

Package: lvm2-2.02.95-10

Parallel NFS (pNFS) is a part of the NFS v4.1 standard that allows clients to access storage devices directly and in parallel. The pNFS architecture eliminates the scalability and performance issues associated with NFS servers in deployment today.

pNFS supports 3 different storage protocols or layouts: files, objects and blocks. The Red Hat Enterprise Linux 6.3 NFS client supports the files layout protocol.

To automatically enable the pNFS functionality, create the /etc/modprobe.d/dist-nfsv41.conf file with the following line and reboot the system:

alias nfs-layouttype4-1 nfs_layout_nfsv41_files

Now when the -o minorversion=1 mount option is specified, and the server is pNFS-enabled, the pNFS client code is automatically enabled.

For more information on pNFS, refer to http://www.pnfs.com/.

Package: kernel-2.6.32-279

Open Multicast Ping (Omping) is a tool to test the IP multicast functionality, primarily in the local network. This utility allows users to test IP multicast functionality and assists in the diagnosing if an issues is in the network configuration or elsewhere (that is, a bug). In Red Hat Enterprise Linux 6 Omping is provided as a Technology Preview.

Package: omping-0.0.4-1

The System Information Gatherer and Reporter (SIGAR) is a library and command-line tool for accessing operating system and hardware level information across multiple platforms and programming languages. In Red Hat Enterprise Linux 6.3, SIGAR is considered a Technology Preview package.

Package: sigar-1.6.5-0.4.git58097d9

Red Hat Enterprise Linux 6 includes fsfreeze as a Technology Preview. fsfreeze is a new command that halts access to a file system on a disk. fsfreeze is designed to be used with hardware RAID devices, assisting in the creation of volume snapshots. For more details on the fsfreeze utility, refer to the fsfreeze(8) man page.

Package: util-linux-ng-2.17.2-12.7

DIF/DIX, is a new addition to the SCSI Standard and a Technology Preview in Red Hat Enterprise Linux 6. DIF/DIX increases the size of the commonly used 512-byte disk block from 512 to 520 bytes, adding the Data Integrity Field (DIF). The DIF stores a checksum value for the data block that is calculated by the Host Bus Adapter (HBA) when a write occurs. The storage device then confirms the checksum on receive, and stores both the data and the checksum. Conversely, when a read occurs, the checksum can be checked by the storage device, and by the receiving HBA.

The DIF/DIX hardware checksum feature must only be used with applications that exclusively issue O_DIRECT I/O. These applications may use the raw block device, or the XFS file system in O_DIRECT mode. (XFS is the only file system that does not fall back to buffered I/O when doing certain allocation operations.) Only applications designed for use with O_DIRECT I/O and DIF/DIX hardware should enable this feature.

For more information, refer to section Block Devices with DIF/DIX Enabled in the Storage Administration Guide.

Package: kernel-2.6.32-279

Filesystem in Userspace (FUSE) allows for custom file systems to be developed and run in user space.

Package: fuse-2.8.3-4

Btrfs is under development as a file system capable of addressing and managing more files, larger files, and larger volumes than the ext2, ext3, and ext4 file systems. Btrfs is designed to make the file system tolerant of errors, and to facilitate the detection and repair of errors when they occur. It uses checksums to ensure the validity of data and metadata, and maintains snapshots of the file system that can be used for backup or repair. The Btrfs Technology Preview is only available on AMD64 and Intel 64 architectures.

Package: btrfs-progs-0.19-12

Red Hat Enterprise Linux 6 features the new LVM application programming interface (API) as a Technology Preview. This API is used to query and control certain aspects of LVM.

Package: lvm2-2.02.95-4

FS-Cache in Red Hat Enterprise Linux 6 enables networked file systems (for example, NFS) to have a persistent cache of data on the client machine.

Package: cachefilesd-0.10.2-1

In Red Hat Enterprise Linux 6.3, the tc utility has been updated to work with the Quick Fair Scheduler (QFQ) kernel features. Users can now take advantage of the new QFQ traffic queuing discipline from userspace. This feature is considered a Technology Preview.

Package: kernel-2.6.32-279

vios-proxy is a stream-socket proxy for providing connectivity between a client on a virtual guest and a server on a Hypervisor host. Communication occurs over virtio-serial links.

Package: vios-proxy-0.1-1

The IPv6 support in IPVS (IP Virtual Server) is considered a Technology Preview.

Package: kernel-2.6.32-279

Rgmanager includes a feature which enables it to utilize Corosync's Closed Process Group (CPG) API for inter-node locking. This feature is automatically enabled when Corosync's RRP feature is enabled. Corosync's RRP feature is considered fully supported. However, when used with the rest of the High-Availability Add-Ons, it is considered a Technology Preview.

Package: rgmanager-3.0.12.1-12

Red Hat Enterprise Linux 6.3 includes support for redundant ring with autorecovery feature as a Technology Preview. Refer to Section 3.7, "Clustering" for a list of known issues associated with this Technology Preview.

Package: corosync-1.4.1-7

The corosync-cpgtool now specifies both interfaces in a dual ring configuration. This feature is a Technology Preview.

Package: corosync-1.4.1-7

As a consequence of converting the /etc/cluster.conf configuration file to be used by pacemaker, rgmanager must be disabled. The risk of not doing this is high; after a successful conversion, it would be possible to start rgmanager and pacemaker on the same host, managing the same resources.

Consequently, Red Hat Enterprise Linux 6 includes a feature (as a Technology Preview) that forces the following requirements:

Package: rgmanager-3.0.12.1-12

The libqb package provides a library with the primary purpose of providing high performance client server reusable features, such as high performance logging, tracing, inter-process communication, and polling. This package is introduced as a dependency of the pacemaker package, and is considered a Technology Preview in Red Hat Enterprise Linux 6.3.

Package: libqb-0.9.0-2

Pacemaker, a scalable high-availability cluster resource manager, is included in Red Hat Enterprise Linux 6 as a Technology Preview. Pacemaker is not fully integrated with the Red Hat cluster stack.

Package: pacemaker-1.1.7-6

Previously, it was not possible to centrally manage host and user SSH public keys. Red Hat Enterprise Linux 6.3 includes SSH public key management for Identity Management servers as a Technology Preview. OpenSSH on Identity Management clients is automatically configured to use public keys which are stored on the Identity Management server. SSH host and user identities can now be managed centrally in Identity Management.

Package: sssd-1.8.0-32

Red Hat Enterprise Linux 6.3 introduces the ability to control the SELinux context of a user on a remote system. SELinux user map rules can be defined and, optionally, associated with HBAC rules. These maps define the context a user receives depending on the host they are logging into and the group membership. When a user logs into a remote host which is configured to use SSSD with the Identity Management backend, the user's SELinux context is automatically set according to mapping rules defined for that user. For more information, refer to http://freeipa.org/page/SELinux_user_mapping. This feature is considered a Technology Preview.

Package: sssd-1.8.0-32

In Red Hat Enterprise Linux 6.3, SSSD includes a new Technology Preview feature: support for caching automount maps. This feature provides several advantages to environments that operate with autofs:

Package: sssd-1.8.0-32

TPM (Trusted Platform Module) hardware can create, store and use RSA keys securely (without ever being exposed in memory), verify a platform's software state using cryptographic hashes and more. The trousers and tpm-tools packages are considered a Technology Preview in Red Hat Enterprise Linux 6.3.

Packages: trousers-0.3.4-4, tpm-tools-1.3.4-2

The SR-IOV functionality of the Emulex be2net driver is considered a Technology Preview in Red Hat Enterprise Linux 6.3. You must meet the following requirements to use the latest version of SR-IOV support:

SR-IOV runs on all Emulex-branded and OEM variants of BE3-based hardware, which all require the be2net driver software.

Package: kernel-2.6.32-279

iSCSI and FCoE boot support on Broadcom devices is not included in Red Hat Enterprise Linux 6.3. These two features, which are provided by the bnx2i and bnx2fc Broadcom drivers, remain a Technology Preview until further notice.

Package: kernel-2.6.32-279

The mpt2sas driver is fully supported. However, when used in the lockless mode, the driver is a Technology Preview.

Package: kernel-2.6.32-279

The dm-thinp targets, thin and thin-pool, provide a device mapper device with thin-provisioning and scalable snapshot capabilities. This feature is available as a Technology Preview.

Package: kernel-2.6.32-279

In Red Hat Enterprise Linux 6.3, the kdump/kexec kernel dumping mechanism is enabled for IBM System z systems as a Technology Preview, in addition to the IBM System z stand-alone and hypervisor dumping mechanism. The auto-reserve threshold is set at 4 GB; therefore, any IBM System z system with more than 4 GB of memory has the kexec/kdump mechanism enabled.

Sufficient memory must be available because kdump reserves approximately 128 MB as default. This is especially important when performing an upgrade to Red Hat Enterprise Linux 6.3. Sufficient disk space must also be available for storing the dump in case of a system crash. Kdump is limited to DASD or QETH networks as dump devices until kdump on SCSI disk is supported.

The following warning message may appear when kdump is initialized:

..no such file or directory

This message does not impact the dump functionality and can be ignored. You can configure or disable kdump via /etc/kdump.conf, system-config-kdump, or firstboot.

The following features are presented as Technology Previews:

Package: kernel-2.6.32-279

The audit package contains the user space utilities for storing and searching the audit records generated by the audit subsystem in the Linux 2.6 kernel. Within the audispd-plugins sub-package is a utility that allows for the transmission of audit events to a remote aggregating machine. This remote audit logging application, audisp-remote, is considered a Technology Preview in Red Hat Enterprise Linux 6.

Package: audispd-plugins-2.2-2

Linux containers provide a flexible approach to application runtime containment on bare-metal systems without the need to fully virtualize the workload. Red Hat Enterprise Linux 6 provides application level containers to separate and control the application resource usage policies via cgroups and namespaces. This release includes basic management of container life-cycle by allowing creation, editing and deletion of containers via the libvirt API and the virt-manager GUI. Linux Containers are a Technology Preview.

Packages: libvirt-0.9.10-21, virt-manager-0.9.0-14

A diagnostic pulse can now be issued on the IPMI interface using the fence_ipmilan agent. This new Technology Preview is used to force a kernel dump of a host if the host is configured to do so. Note that this feature is not a substitute for the off operation in a production cluster.

Package: fence-agents-3.1.5-17

KVM can now virtualize a performance monitoring unit (vPMU) to allow virtual machines to use performance monitoring. Additionally it supports Intel's "architectural PMU" which can be live-migrated across different host CPU versions, using the -cpu host flag.

With this feature, Red Hat virtualization customers are now able to utilize performance monitoring in KVM guests seamlessly. The virtual performance monitoring feature allows virtual machine users to identify sources of performance problems in their guests, using their preferred pre-existing profiling tools that work on the host as well as the guest. This is an addition to the existing ability to profile a KVM guest from the host.

This feature is a Technology Preview in Red Hat Enterprise Linux 6.3.

Package: kernel-2.6.32-279

KVM in Red Hat Enterprise Linux 6.3 now supports dynamic virtual CPU allocation, also called vCPU hot plug, to dynamically manage capacity and react to unexpected load increases on their platforms during off-peak hours.

The virtual CPU hot-plugging feature gives system administrators the ability to dynamically adjust CPU resources in a guest. Because a guest no longer has to be taken offline to adjust the CPU resources, the availability of the guest is increased.

This feature is a Technology Preview in Red Hat Enterprise Linux 6.3. Currently, only the vCPU hot-add functionality works. The vCPU hot-unplug feature is not yet implemented.

Package: qemu-kvm-0.12.1.2-2.295

KVM Virtualization's storage stack has been improved with the addition of virtio-SCSI (a storage architecture for KVM based on SCSI) capabilities. Virtio-SCSI provides the ability to connect directly to SCSI LUNs and significantly improves scalability compared to virtio-blk. The advantage of virtio-SCSI is that it is capable of handling hundreds of devices compared to virtio-blk which can only handle 25 devices and exhausts PCI slots.

Virtio-SCSI is now capable of inheriting the feature set of the target device with the ability to:

This feature is a Technology Preview in Red Hat Enterprise Linux 6.3

Package: qemu-kvm-0.12.1.2-2.295

KVM's power management features have been extended to include native support for S4 (suspend to disk) and S3 (suspend to RAM) states within the virtual machine, speeding up guest restoration from one of these low power states. In earlier implementations guests were saved or restored to/from a disk or memory that was external to the guest, which introduced latency.

Additionally, machines can be awakened from S3 with events from a remote keyboard through SPICE.

This feature is a Technology Preview and is disabled by default in Red Hat Enterprise Linux 6.3. To enable it, select the /usr/share/seabios/bios-pm.bin file for the VM bios instead of the default /usr/share/seabios/bios.bin file.

The native, in-guest S4 (suspend to disk) and S3 (suspend to RAM) power management features support the ability to perform suspend to disk and suspend to RAM functions in the guest (as opposed to the host), reducing the time needed to restore a guest by responding to simple keyboard gestures input. This also removes the need to maintain an external memory-state file. This capability is supported on Red Hat Enterprise Linux 6.3 guests and Windows guests running on any hypervisor capable of supporting S3 and S4.

Package: seabios-0.6.1.2-19

This feature provides KVM support for stable technology that is already used in data center with bare metal systems. SNMP is the standard for monitoring and is extremely well understood as well as computationally efficient. System monitoring via SNMP in Red Hat Enterprise Linux 6 allows the KVM hosts to send SNMP traps on events so that hypervisor events can be communicated to the user via standard SNMP protocol. This feature is provided through the addition of a new package: libvirt-snmp. This feature is introduced as a Technology Preview.

Package: libvirt-snmp-0.0.2-3

Virtualization and cloud products that run networking work loads need to run wire speeds. Up until Red Hat Enterprise Linux 6.1, the only way to reach wire speed on a 10 GB Ethernet NIC with a lower CPU utilization was to use PCI device assignment (passthrough), which limits other features like memory overcommit and guest migration

The macvtap/vhost zero-copy capabilities allow the user to use those features when high performance is required. This feature improves performance for any Red Hat Enterprise Linux 6.x guest in the VEPA use case. This feature is introduced as a Technology Preview.

Package: qemu-kvm-0.12.1.2-2.295

The numad package provides a daemon for NUMA (Non-Uniform Memory Architecture) systems that monitors NUMA characteristics. As an alternative to manual static CPU pining and memory assignment, numad provides dynamic adjustment to minimize memory latency on an ongoing basis. The package also provides an interface that can be used to query the numad daemon for the best manual placement of an application. The numad package is introduced as a Technology Preview.

Package: numad-0.5-4.20120522git